1. Field of the Invention
This invention relates to a command generation system by which a command to a numerical-controlled machine tool or the like can be generated smoothly so that the command undergoes a smooth and substantial change.
2. Description of the Prior Art
In a system which calculates a given digital quantity in a predetermined relation and converts the calculated result to analog form to apply a command to a controlled object, such as, for example, a numerical control equipment, it is sometimes necessary (according to the characteristics of the controlled object) to generate a command so that the command value may vary smoothly, that is, may not undergo an abrupt change. A typical example is a velocity command value which is applied to a servo system of a numerical-controlled machine tool. In this case, a rapid change in the velocity command value results in the machine tool being subjected to a great shock, and hence is not preferred. In general, however, since a certain period of time is required for a digital arithmetic unit to output a calculated result, if an increase or decrease in the calculated result is abrupt as compared with the time needed for the calculation, then the difference becomes great between the calculated result obtained at a certain point of time and the immediately preceding calculated result, and the resulting command value supplied from a D/A converter to the controlled object inevitably undergoes a substantial change. This must be avoided for the reason mentioned above.